As shown in FIG. 4, in a hydraulic excavator 1 as a work machine, an upper swing body 3 rotated by a swing motor 3m is provided on a lower traveling body consisting of left and right traveling devices 2 driven by left and right traveling motors 2m respectively, and a cab 4 and an implement device 5 are mounted with respect to the upper swing body 3. In the implement device 5, a base end of a boom 6 vertically rotated by a boom cylinder 6c is pivotally supported on the upper swing body 3, a stick 7 rotated by a stick cylinder 7c is pivotally supported on a top end of the boom 6, and a bucket 8 rotated by a bucket cylinder 8c is pivotally supported on a top end of the stick 7.
In such a hydraulic excavator, in the cab 4, travel pedals and travel levers, with which the left and right traveling devices 2 of the lower traveling body are operated, are normally provided on a front floor of an operating seat.
In the case of performing rough traveling operation, travel pedal operation by foot may be performed. However, the pedal operation is unsuitable for fine operation. Accordingly, in the case of performing the fine operation by the travel lever, it is necessary to release either of the hands from the operating levers for implement functions and swing, which are used for swing operation of the upper swing body 3 and the implement device 5 and provided left and right of the operating seat, and to extend a hand to operate the front travel lever.
Additionally, in the case of separately operating the left and right travel levers, both hands are required to be extended forward.
In the case of thus providing the travel levers in the front of the operating seat, the travel levers become an obstruction when an operator attempts to get in and out of the cab 4. Alternatively, the operator must shift the operating lever from one hand to the other for operating the travel lever and change his posture.
For example, Japanese Laid-Open Patent Publication No. 6-136778 (Page 4, FIG. 9); Japanese Laid-Open Patent Publication No. 7-32901 (Page 3, FIG. 2); Japanese Laid-Open Patent Publication No. 2002-323931 (Page 4, FIG. 1); Japanese Laid-Open Patent Publication No. 2004-100397 (Pages 7 and 15-17, FIGS. 1 and 11) disclose, as means for solving the problem, a travel operating lever in the vicinity of the operating levers for implement function and swing provided next to the operating seat.
In this case, although getting in and out for the operator is improved, the operator must, as before, shift the operating lever from one hand to the other for traveling operation, and thus a new space for the travel operating lever is required next to the operating seat.
On the other hand, for example, Japanese Laid-Open Patent Publication No. 7-119710 (Pages 2 and 3, FIG. 1) and Japanese Laid-Open Patent Publication No. 2000-27238 (Pages 4-7, FIG. 1) propose a constitution that one of the operating levers for implement function and swing can be used as the travel operating lever by means of a switching device.
Further, Japanese Laid-Open Patent Publication No. 2004-100397 (Pages 7 and 15-17, FIGS. 1 and 11) and Japanese Laid-Open Patent Publication No. 9-165788 (Pages 3 and 4, FIGS. 3 and 4) propose a constitution that left and right implement function and swing levers can be independently used for operation of left and right travel devices.
In these cases, the case of providing the switching device in addition to the operating levers provides no great difference from the case of shifting the operating lever from one hand to the other. Additionally, in the case where the switching device is attached to the operating lever, it is difficult for the operator to understand whether the operation has changed, and, at that point in time, it becomes necessary to think about which device is being operated by the operating lever.